Life

Eat and Drink to Beat the Heat

9 steps to dialing in a race-week hydration and nutrition strategy that will go the distance on the big day.

by Katya Meyers

A few years ago, I raced IRONMAN 70.3 Philippines and encountered conditions so hot and humid the locals nicknamed a portion of the run course "the rice cooker." As I ran through the rice paddies I could feel the steam rising from the pavement. A few miles from the finish, my mouth began to feel dry and cottony ... I was starting to feel a little overcooked. And, as anyone who has ever had to clean the bottom of a burnt pot of rice can attest, bad things happen when water runs low. I finished, but undoubtedly my race was impacted by imperfect fueling.

Memorial Hermann IRONMAN Texas is just around the corner, reminding us that hot conditions are coming our way. Increased temperatures and humidity strain the body in more ways than one. The heat index can certainly create direct race day discomfort, but where many athletes really have issues is in the realm of nutrition and hydration.

According to Brett Singer, RD, LD, of the Memorial Hermann IRONMAN Sports Institute in the Woodlands, Texas, even a two to three percent reduction in weight due to water loss can have deleterious effects. This effect is magnified in hot environments. One recent study indicated a five to eight beat increase in heart rate per minute for every one percent in body weight lost to dehydration. As any type A triathlete (i.e. all of us) can tell you, that’s a lot!

What can you do to execute a nutrition plan that will beat the heat? Hint: Part of your job starts during the week leading up to the race. Read on for both pre-race and race-day strategies that will keep you out of hot water ... in the fueling department, anyway.

1. Don’t start in the red. Dehydration increases heat storage and reduces a person's ability to tolerate heat strain—decidedly not a good thing at the start of an endurance event. Staying hydrated in the days leading up to the race can be a challenge, given long travel, the break from normal routine and the temptation to avoid drinking so you don’t have to enter the porta potty at the pre-race expo. Nevertheless, it’s essential to avoid starting a race dehydrated if you want to perform at your best.

2. Keep your friends close, your water bottle closer. Most sports dietitians recommend a weakly concentrated sports drink (four to eight percent glucose concentration) in the days leading up to completion for hydration and electrolyte balance, including morning of the race. Race week, your trusty water bottle should always be close at hand.

3. Step on the scale. Any drop in your baseline weight in the days leading up to the race can indicate dehydration. A daily weigh in performed at the same time each day can keep you on track.

Singer, who advises athletes of all levels—from first timers to veteran IRONMAN competitors in their fueling strategy—suggests the following protocol: "If urine is dark, five to seven milliliters of fluid per kilogram of body weight is the rule of thumb. If urine is still dark two to three hours prior to the event, then two to three milliliters per kilogram is a more appropriate range. Anything more, and your body won’t absorb it." Translation: you’ll just pee it out.

5. Repeat after me, WATERmelon. Watermelon, like most fruits and veggies, has a high water content. Because they are usually also high in fiber, I recommend minimizing consumption 24 hours out, but earlier in race week, they provide a great source of H20.

6. Pass the salt. Unless you have hypertension, research confirms sodium loading before exercising in the heat supports fluid balance and endurance during exercise. In addition to the salt shaker, other good choices include pretzels, broth-based soups, canned veggies and most cheeses. On race day, replenishing sodium during longer events is often necessary in hot conditions. Sodium loss varies considerably, ranging from 200 to 1500 milligrams per liter of sweat. Other electrolytes—K+, Mg, etc. are lost, but not at a rate that you have to consciously replenish. Salt tabs are one of the most convenient concentrated forms (check the sodium content—it varies greatly from brand to brand), but sports drinks, gels and bars are also electrolyte sources. If you know you’re a salty sweater, aim for the higher end of that range.

7. Get a handle on your sweat rates. According to Singer, sweat rates vary from half a liter to two liters per hour. To help athletes zero in on their individual hydration needs, he gets his clients to perform sweat tests. This test is best done on heavy training days by taking pre- and post-workout weights, in the buff. Subtract your post-training weight from your pre-training, weight, convert the weight to ounces, and add the number of fluid (in ounces) that you consumed in training. Divide by the hours trained to get your hourly sweat rate—at that intensity and in those environmental conditions. Repeat as necessary, ideally in the conditions you will be racing in, to keep tabs on your sweat rate.

8. Sip it. This is not the time to practice your chugging capabilities. Save that for the beer mile. A few sips every 15 to 20 minutes will enhance your fluid absorption rate, particularly during the event when digestion is slowed. A sloshing stomach or distended belly means you’ve over done it with either food or water. Time to back off.

9. Too much of a good thing. Though relatively uncommon, hyponatremia is a serious condition resulting from electrolyte imbalance—often a result of "overhydrating" with low-electrolyte sources, like plain water. Unfortunately, the main symptoms—lethargy, confusion, and nausea—mimic dehydration, and it can be mistreated. Always be sure to include an electrolyte source in your race fueling plan.

Katya Meyers is a pro triathlete and endurance coach. When not swimming, biking, or running, this Kentucky farm girl turned SoCal triathlete loves wearing heels, nerding out on biology and discovering hikes in remote areas of South East Asia. Find out more at katyameyers.com or say hi on Twitter @katyameyers.